site drainage areas (sdas) vs. contributing drainage areas ......da#1 = 65,496 sf da#2 = 66,971 ft2...
TRANSCRIPT
Site Drainage Areas (SDAs) vs. Contributing Drainage Areas (CDAs)
Building = Major Substantial Improvement (0.8”)
Land Area = Major Land Disturbing (1.2”)
• Building is undergoing a complete renovation.
• Surrounding land is being regraded with new sidewalks and construction of an underground parking facility.
DA#1 = 65,496 ft2
DA#2 = 66,971 ft2
Site Drainage Areas
DA#1 = 65,496 ft2
DA#2 = 66,981 SF
Major Land Disturbing (1.2-inch) Land Area (ft2) Rv SWRv (ft3)
Impervious Cover (sidewalks, etc.) 11,197 0.95 1,064
Compacted Cover (grass, landscaping) 43,685 0.25 1,092
BMP (bioretention) 1,489 0.95 141
MLD Total 2,297
Major Substantial Improvement (0.8-inch) Land Area (ft2) Rv SWRv (ft3)
Impervious Cover (building) 9,125 0.95 578
Total 65,496 2,875
Site Drainage Area #1
DA#1 = 65,496 SF
DA#2 = 66,971 ft2
Major Land Disturbing (1.2-inch) Land Area (ft2) Rv SWRv (ft3)
Impervious Cover (sidewalks, etc.) 11,704 0.95 1,112
Compacted Cover (grass, landscaping) 27,289 0.25 682
BMP (bioretention, green roof) 9,878 0.95 938
MLD Total 2,732
Major Substantial Improvement (0.8-inch) Land Area (ft2) Rv SWRv (ft3)
Impervious Cover (building) 18,100 0.95 1,146
Total 66,971 3,878
Site Drainage Area #2
Total SWRv for Site
Site Drainage Area #1 2,875 ft3
Site Drainage Area #2 3,878 ft3
Total = 6,753
BMP Locations
Bioretention
Green Roof
Contributing Drainage Areas
A
B
C
D
E
Site Drainage Areas
DA#1 = 65,496 SF
A
SDA #1 SWRv (1.2-inch) = 2,875 ft3
Land Cover Type CDA
Area (ft2) Rv SWRv (ft3)
(1.7-in)
Impervious Cover 18,067 0.95 2,432
Compacted Cover 36,566 0.25 1,295
BMP 1,489 0.95 200
Total 56,122 3,927
Storage Volume Bioretention 3,076 ft3
Maximum Retention Volume 3,076 ft3
DA#2 = 66,981 SF B
C
D
E
SDA #2 SWRv (1.2-inch) = 3,878 ft3
BMP SWRv (ft3) (1.7-inch) Storage Volume (ft3)
B 997 1,047
C 1,314 1,402
D 923 859
E 1,241 1,157
Total 4,475 4,465
Maximum Retention Volume 4,327 ft3
Total SWRv for Site
Site Drainage Area #1 2,875 ft3
Site Drainage Area #2 3,878 ft3
Total = 6,753
Maximum Retention Volume BMP A 3,076 ft3
Maximum Retention Volume BMPs B - E 4,327 ft3
Total = 7,403 Met their stormwater obligation!